A data center is a facility for centrally installing and operating a large amount of hardware including a server and communication equipment. Some of the data centers may be installed as part of an existing building. In recent years, cloud services have been developed and a scale of the data center has been continuously increasing. It is desired to achieve further power saving in a large-scale data center.
To construct such a large-scale data center, a container-type data center of which initial investment cost is low is proposed. The container-type data center is a portable data center that can be additionally installed according to a whole scale of the data center, and has an effective configuration to reduce total power consumption and realize power saving, so that it has been rapidly spreading.
Examples of equipment installed in such a container-type data center include network devices, storage devices, and computers such as servers. Some of the equipment installed in the data center include heat generation components such as a central processing unit (CPU) as an arithmetic processing unit or a memory as a storage device. The temperatures of these components that have risen are reduced by air conditioning. This reduces in turn the temperature in the container.
Examples of an air conditioning system of the container-type data center include an air conditioner system using a chiller. When the air conditioner system is used, air is cooled by using electric power. Therefore, there is a risk that a power consumption amount increases in the air conditioner system. Accordingly, an outside-air cooling system has been focused on in terms of power saving of the air conditioning. Specifically, a direct outside-air system, which is one of the air conditioning systems effective for power saving, takes outside air in the container-type data center to lower the temperature of a heat generating component such as a CPU or of a container using the outside air.
As the direct outside-air system, proposed is a related art in which air is sucked in from the outside of the container using a large air conditioning fan mounted to the container and a server takes the air into its housing its own fan to cool a heat generation component and the like (for example, refer to a product catalogue of SGI® IceCube™ Air, SGI Japan, Ltd.).
In such a container-type data center using the direct outside-air system, a plurality of fans that can provide a sufficient volume of air for cooling the server are arranged. Because two or more fans are arranged, redundancy of the fans may be secured.
Example of the cooling fan for the electronic equipment include a related-art configuration including a fan that cools the entire electronic equipment and a fan that locally cools the electronic equipment (for example, refer to Japanese Laid-open Patent Publication No. 2009-59033). In addition, there is a related art for causing temperature-controlled air to flow through equipment to be measured and evaluates a heat radiation characteristic of the equipment (for example, refer to Japanese Laid-open Patent Publication No. 08-29210). There is also a related art for detecting a current value of a power conversion circuit in a welding machine to select the minimum number of fans needed (for example, refer to Japanese Laid-open Patent Publication No. 11-28569).
However, the fan operates by pulse driving, whereby the fan rotates at the minimum number of revolutions by the pulse driving or more. When the largest possible fan is used for saving power, even if the fan rotates at the minimum number of revolutions, the volume of air becomes excessive, for example, in a case where all of the servers are in an idle state. This means that electric power is wasted. When some of the fans are stopped to adjust the volume of air, wind is not sent to some areas. Accordingly, face wind speed cannot be obtained uniformly on a rack on which the server is disposed.
Even when using the related art including the fan that cools the entire electronic equipment and a fan that locally cools the electronic equipment, it is difficult to reduce the excessive volume of air caused at the minimum number of revolutions. When using the related art for causing the temperature-controlled air to flow through the equipment to be measured, the volume of air can be adjusted in a range of the minimum number of revolutions or more, but the volume of air cannot be reduced to or below the volume of air at the minimum number of revolutions. In addition, even when using the related art for selecting the minimum number of fans needed based on the current value, the uniform face wind speed cannot be obtained because the number of fans to be used is reduced.